3.7.43. Circuit

A constraint such that its initial or its final graph corresponds to zero
(e.g., 𝚌𝚞𝚝𝚜𝚎𝚝), one
(e.g., 𝚌𝚒𝚛𝚌𝚞𝚒𝚝) or several
(see, e.g., the 𝚌𝚢𝚌𝚕𝚎, and
𝚜𝚢𝚖𝚖𝚎𝚝𝚛𝚒𝚌_𝚊𝚕𝚕𝚍𝚒𝚏𝚏𝚎𝚛𝚎𝚗𝚝 constraints)
vertex -disjoint circuits.